Ururka birta kaarboon-yar ee heerkulka qolka ee ferrite iyo pearlite, haddii ay jirto qaab dhismeedka band ee ferrite iyo pearlite xariijin beddelka ururka.Qaab dhismeedka tubbada birta kaarboon hoose ee bilaa-xun, laga bilaabo heerkulka qolka ilaa heerkulka caadiga ah, marka heerkulka Ac1, isbeddelka eutectoid uu dhaco, isbeddelka pearlite ee austenite.Xaaladdan oo kale, qaybaha ma aha austenite isku mid ah, iyadoo heerkulka kulaylku ka badan yahay Ac3, ferrite xal adag waa la dhammeeyey, ka dibna qaab-dhismeedka birta waxaa loo rogaa hal-waji austenite, sida heerkulku sii wadaan in ay kordhiyaan iyo caadiga ah incubation heerkulka. austenite gabi ahaanba labis.

Laga soo daayay qaboojinta heerkulka caadiga ah Ka dib, marka heerka qaboojinta birta si loo baabi'iyo qaab dhismeedka weyn ee qaboojinta heerka qaboojinta muhiimka ah (ie, xakamaynta ferrite ee heerka qaboojinta austenite), tuubada birta ee eutectoid ferrite jirka waa la xakameynayaa, si ferrite ma soo da'in oo ka saarta dareeraha hadhaaga austenite, iyo marka heerkulku hoos u dhaco iyada oo la kordhinayo heerka qaboojinta, mana dhici doonto mar kale da'da pro-eutectoid ferrite, iyada oo si toos ah loo qaboojiyey badeecada austenite eutectoid ferrite + cementite, laakiin si ka duwan eutectoid Halabuurka birta, oo loo yaqaan "pseudo-eutectoid" sababtoo ah "pseudo-eutectoid" ma jiro eutectoid ferrite jiritaanka jirka, sidaas darteed qaab-dhismeedka yar ee qaab-dhismeedka birta ee birta ma jiro.Dahaarka tuubada ee la dubay kadib heerkulka caadiga ah ka dib, heerka qaboojintu wuu ka yar yahay qaab dhismeedka birta si loo baabi'iyo heerka qaboojinta muhiimka ah ee qaboojinta tartiib tartiib ah, marka heerkulku hoos loo dhigo Ac3, marka hore wuxuu baabi'iyay birta kaarboon austenitic aagga roobka ferritic. -Gobolka saboolka ah ee wajiga waalidka ee ku saabsan qaab dhismeedka band), iyadoo hoos u qaboojinta gaabis ah iyo heerkulka eutectoid ferrite mugga waxaa si tartiib tartiib ah kordhay ilaa qabow si Ac1 marka austenite galay pearlite, heerkulka qolka The microstructure ee birta ah, waxa u muuqday ferrite iyo pearlite bands. banded isla urur.